On the Trail of Osama bin Laden: Scientists Use Biological Tracking Models to Pursue America's Most Wanted

Oct 1, 2009

Regional analysis of city islands within a 20-km radius of bin Laden's last known location (red dot).

The United States military's attempts to track down Osama bin Laden in the seven-plus years since the World Trade Center attacks have been notoriously fruitless. But a new study suggests the way to find America's most wanted criminal is to treat him like an endangered species. In the study, released in MIT International Review, University of California-Los Angeles geographers Thomas Gillespie and John Agnew modeled the terrorist leader's possible whereabouts by using the same techniques conservationists use to track the dispersal of animals and likely migration patterns. Using a variety of criteria specific to Osama bin Laden's needs—electricity, room for his entourage, health problems—the study isolates three buildings in the remote Pakistani town of Parachinar in the Federally Administered Tribal Areas as the most likely hideout. (The paper was submitted to the FBI before it went to the MIT journal and, according the FBI, it was forwarded to the appropriate personnel and is part of an active investigation.) There is a bounty of criticism to the specificity of the finding. In a response posted by the MIT International Review, Murtaza Haider, from the Ted Rogers School of Management at Ryerson University, Toronto, says that while "the geography professors at UCLA may have used spatial analysis to determine the probable hideout of Osama; they certainly overlooked history and anthropology, which would have explained the gory sectarian rivalries between the Shiites of Parachinar and the Sunni supporters of Osama bin Laden." It is highly unlikely that a Shiite town would house Osama bin Laden, he says. "This is yet another example of technical analysis devoid of any understanding of the local socio-cultural and political contexts," Haider says. Still, others defend Gillespie and Agnew's paper as a valuable thought experiment.

A couple of biological models came in handy in the pursuit of bin Laden. The first is called distance-decay theory, which simply means that because conditions can change rapidly as you travel, the likelihood of finding an animal drops off exponentially the further you get from a place where it's known to live. The other is called island biogeography, which refers to outposts of habitable territory surrounded by uninhabitable territory. Island biogeography, the researchers say, shows that more species move to a large, nearby island than to a small, far-flung one. Biologist E.O. Wilson once showed this by fumigating small islands (pdf) in the Florida Keys and tracking how long they required to repopulate. Sure enough, the nearer, bigger ones repopulated first.

When you combine these two models with information about the particular animal you're seeking, you can narrow down the places where it might be found, says landscape ecology professor Frank Davis of the University of California, Santa Barbara. "You're trying to map places with higher or lower probability," he says. Currently, researchers use these models to guess where species will migrate when climate change alters their habitat or to determine a species-critical habitat—areas crucial to a species' survival. Gillespie says that several years ago scientists used the same tactics, unsuccessfully, to try to find the ivory-billed woodpecker, which is thought to have gone extinct in the 1920s. He also uses them to track rare species in the tropics.

So how does that apply to the world's most wanted terrorist? Distance-decay suggests that bin Laden wouldn't travel too far from his last known whereabouts, Tora Bora in the Afghan mountains. With animals, it's often environmental conditions that keep them from straying too far, but bin Laden's problem is different. "It's his political habitat," Davis tells PM. The further he goes from the Afghanistan-Pakistan border regions, the more likely it becomes that he would enter an unfriendly area and be caught. Parachinar, however, housed mujahedin fighters in the 1980s and Agnew and Gillespie say that it likely hosts Taliban fighters today. And island biogeography suggests that bin Laden would stand a better chance staying hidden in a larger city than in a smaller one. Parachinar is the largest such city in the region.

Those two factors led Agnew and Gillespie to the town of Parachinar as a particularly likely bin Laden hideout. But the city boasts hundreds of thousands of residents—knowing the terrorist leader was there wouldn't guarantee that you could find him. So the researchers factored in more specific information about bin Laden. He's tall (well over 6 ft), needs a dialysis machine to survive, moves with an entourage and requires protection from aerial view. That means he requires a building with multiple rooms, electricity, tree cover and ceilings tall enough for him to walk around. Only three buildings in Parachinar fit the description, the researchers say.

Gillespie told PM that this study is being released now because academics are sometimes loath to jump into something so politically charged—he usually studies tropical plants and animals, but students in his remote sensing class pushed him toward this "more interesting" topic. Furthermore, satellite imaging wasn't good enough to do this project until the release of programs like Google Earth and GeoEye. "The technology caught up with the question," he says.

The government agencies that have been pursuing bin Laden for years have yet to release much public data about their methods, the researchers say, so their study is based upon what assumptions they could make, including his last definitely known location, and their dispersal models. While it's tough to know how accurate Gillespie and Agnew are based on the little information that is at their disposal, they argue in the report that the U.S. government ought to at least disprove their idea that bin Laden is in one of these three buildings in Parachinar. And what of the popular rumor that bin Laden lives in a cave? Don't count on it, the researchers say. He'd need supplies brought in, an entrance and a ventilation system—activity the United States would likely see from space. —Andrew Moseman

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